1. Field of the Invention
The invention relates to propulsion engines of the turbojet type which are particularly suitable for supersonic aircraft.
A development sought in the design of propulsion engines in order to improve their adaptability to the variable conditions of use in the different flight phases of supersonic aircraft, is to provide a variable operating cycle for the engine. The aim, in particular, is to reconcile the need to obtain a powerful thrust per unit of throughput and, consequently, a high speed for the gases on ejection at supersonic speeds, with the need to reduce the speed of ejection at subsonic speeds, particularly during take-off, so as to limit the noise nuisance.
2. Description of the Prior Art
One solution meeting these aims is described in EP-A-0 076 192, and provides for two connected coaxial propulsion units, an inner unit and an outer unit. However, this structure includes two separate combustion chambers and several rotary bodies with concentric shafts, which renders implementation and operation highly complex.